Added multi-chain notebook to the website yml

Author: andrewherren

mkdocs.yml

@@ -60,6 +60,7 @@ nav:
       - 'Demo': python_docs/demo/index.md
       - 'BART': python_docs/demo/supervised_learning.ipynb
       - 'BCF': python_docs/demo/causal_inference.ipynb
+      - 'Multi-Chain Inference': python_docs/demo/multi_chain.ipynb
       - 'Heteroskedastic BART': python_docs/demo/heteroskedastic_supervised_learning.ipynb
       - 'Multivariate treatment BCF': python_docs/demo/multivariate_treatment_causal_inference.ipynb
       - 'Model Serialization': python_docs/demo/serialization.ipynb